china is also a victim of internet hacking attacks. we have stressed many times that hacking attacks are transnational and anonymous. determining their origins is extremely difficult. we don't know how the in evidence this so-called report can be tenable. >> woodruff: still, the mandiant findings are the most detailed accusations yet against china over hacking. more generally, a u.s. national intelligence estimate said this month that china is tearing out a major cyber espionage campaign against american targets and apple said today it was hacked by the same group that attacked facebook last week. both companies said no data was compromised and both traced the attacks back to china. the report note the report noted there have been more than 140 different victims since 2006, and that the chinese unit maintained access to those networks for nearly a year on average. for more on this, we turn to: richard bejtlich, the chief security officer for mandiant, the firm that issued the report. and christopher johnson, a senior adviser who closel